Although computer systems can store a wealth of information, it can often be difficult for users to find or retrieve a specific document or piece of information. In particular, the amount of information and content stored by and available from computing devices and the Internet continues to grow exponentially. Given the vast amount of information, search engines and other data querying tools have been developed to facilitate searching for documents and information from data stores.
Typically, search engines and other data querying tools are configured to interact with and search a single data store. However, users may often wish to simultaneously search multiple data stores, known as federated searching. Federated search scenarios, though, present challenges as data store providers often maintain their data in data stores having different structures, which makes it difficult to search over the multiple data stores. In particular, a schema is typically used to provide information about the structure of the data in a structured data store. Different data stores typically use a different schema, making it difficult to operate seamlessly over all the data stores.